The long-term objective of our program is to develop the replacement x- ray cone (RXC) so that it will become the x-ray cone of choice in dental offices. The RXC gives a LCD display of the x-ray film in the patient's mouth, thereby permitting a rapid alignment of the x-ray cone with the center of the film. With the assured alignment the beam cross section can be collimated to the dimensions of the film. In contrast, the standard x-ray cone has a cross-sectional area 3 to 4 times the film area. This gives the patient 3 to 4 times the x-ray dose necessary for a film exposure. The RXC is also designed so that an x-ray can only be taken when there is alignment, thereby preventing the occurrence of cone cutting.